Tube expander with rotary work engaging members



May 20, 1958 J. A. JORGENSEN 3 TUBE EXPANDER WITH ROTARY' WORK ENGAGING MEMBERS Filed June 23, 1953 4 Sheets-Sheet 1 k G, /////l/////////////r////////4g;

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J. A. JORGENSEN TUBE EXPANDER WITH ROTARY WORK ENGAGING MEMBERS May 20, 1958 Filed June 23, 1953 INVENTOR. 0hr enA.Jo ens United States Patent 6 TUBE EXPANDER WITH ROTARY WORK ENGAGENG MEMBERfi Jorgen A. .lorgensen, Massiiion, Ohio, assignor to The Griscom-Russeil Company, Massillon, @hio, a corpo ration of Delaware Application June 23,1953, Serial No. 363,583

4 Claims. c1. ma -s2 The invention relates to tube expanders and. more particularly to a tool having rotary work engaging members which roll or cold work the interior of the end of a metal tube for expanding the same to secure. such tube end within an opening or hole in a tube sheet or header of a shell or drum and tube heat exchanger structure; and this invention constitutes an improvement on the tube expander tool shown in the Knowlton Patent No. 2.546,756.

in the fabrication of shell and tube heat exchanger structures it is necessary to mount a large number of tubes in tube sheets which form parts of such structures; and it is necessary to secure the ends of such tubes in openings in the tube sheets in a fixed manner. Normally, the tube ends are secured within the tube sheet openings by internally expanding the ends of the tubes within such tube sheet openings by the use of tools commonly called tube expanders.

However, numerous difliculties have been encountered in the use of prior tube expander tools for performing the tube expanding step in the fabrication of shell and tube heat exchangers particularly where the tube wall thickness is relatively thin, or where the tube diameter is relatively small, or where there are variations in the tube wall thickness or inside tube Wall diameter or inside tube sheet opening diameter, or where the tubes are formed of certain metals in connection with which the expanding cold working of a thin walled tube of such metal must be very carefully controlled.

In the use of prior tube expander tools of certain types, the extent of tube rolling is dependent on the skill or judgment of the tool operator.

in certain types of tube expander tools, attempts have been made to reduce operator skill requirements for obtaining proper tube expansion, by equipping. the tube expander tools with drive motors which automatically shut off when a predetermined torque has been developed. A disadvantage in the use of such tube expander tools is that variations in tube wall thickness, or inside tube wall diameter, or inside tube sheet hole diameter may shut oil the tube expander tool drive at alime when the tube is not completely expanded, or, in other cases sometimes not until the tube has been overexpanded.

A further difficulty encountered in the use of certain types or" tube expander tools is that usually torque is transmitted from the drive motor to the expanding rollers through a mandrel surrounded by the expanding rollers. Where small diameter tubes are being expanded, tie mandrel of necessity must be so small that tool breakage is frequently encountered and becomes a serious and costly problem.

The tube expander tool of the Knowlton Patent No. 2,546,756 overcomes the tool breakage problem by eliminating torque transmission through a mandrel, but it has the disadvantage that a difierent sized mandrel mustbe used substantially for every different tube wall thickncss or tube Willi inside diameter, thus being expensive 2,835,307 Patented May 20, 1958.

2. and time consuming in operation because. of the frequent mandrel changes required.

Another dithcul'ty in the. use of prior tube expander, tools is that their operation depends on progressive. expanding rolling. of the tube end. inward of the tube from the outer endof .thev tube. within. the tube holeiri. the tube sheet, in; entirety or as an initial, operation. of; the expanding tool. Such procedure may cause difficulty. in the later use ofthe heat exchanger by increasing v the tendency of the tubes to buckle when subsequently heated, because of placing. the metal of the tubes under compressionbetween spaced tube sheets when expanding the, second end of a tube in a second tube sheet progressively inward of the tube from the end thereof after. the first. end of the tube has. been secured and'fixed byexpanding, within a tube hole in a first tube sheet.

I have discovered a new tube expander tool construction, the use of which avoids; the foregoing difficulties, and with which smaller tubes can be expanded withless; danger of tool'breakage and at the same time theinside; diameter of the expanded tube can be controlledtto. any desired value and the expansion can be performed. with. as many passes as may be desired or required withoutv changing the mandrel, and in the use of'which the tube. expander can be withdrawn at any time without damage to the tube or the expander.

Accordingly, it is a general objectof the present. invention to provide a new tube expander tool construction with which it is possible to. predetermine theextent of. the tube rolling for tube expansion in a manner. independent of the judgment or skill of the individual who. may be operating the. tool.

Moreover, it is an object of thepresent inventionv to. provide a new tube expander tool construction utilizing, a drive motor for the tube expanding rotary work. en? gaging members or rolls. which shuts oil when a predetermined torque has been developed. correlated withv the. desired inside tube diameter after expansion,. for locat-. ing the expanding work engaging rolls at the desired. predetermined setting for tube rolling; and Whichmotor is then operated at full line current without torquecutw off to complete the tube expanding rolling operation. to the predetermined extent or predetermined expanded tube, diameter.

Furthermore,.it isan object of the present invention.

to provide a tube expander tool construction which will.-

roller expand a tube end within a tube hole inal tube. sheet to the desired predetermined. extent, without. regard to variations in tube wall thickness, or insidetube. wall diameter, or inside tube sheet hole diameter, so as. to obtain the desired tube expansion without either under-. expansion or over-expansion.

Moreover, it. is an object of the present invention. to; provide a new tube expander tool constructionvin whichv torque from the drive motor is transmitted through an expander cage directly to. the expanding rollers without transmitting torque through a mandrel used for setting; the rollers to obtain the desired degree of expansion, thereby eliminating the problem of tool breakage when expanding tubes of relatively small diameter.

Also, it is an object of the present invention to provide a new tube expander tool construction having a roll setting mandrel and a torque drive through an expander cage directly from the drive-motor to the expanding rollers, in which the same mandrel may be used without change for expanding tool walls of. diflferent thicknesses and different inside diameters within the. size capacity of the particular tool.

Likewise, it is an object of the present inventionto provide a new tube expander tool construction which the end of the tube, rather than progressively inward from the end of the tube, in order to avoid any disturbance of the metal in the'tube between expanded tube ends when .a tube expanding operation is performed on both ends of the tube.

Moreover, it is an object of the present invention to provide a new tube expander tool which may be operated to feed the tube expanding rollers to a desired setting to obtain a predetermined expansion or extent of tube rolling, and which may then be operated to expand the tube to a constant inside expanded diameter under direct drive uniformly and continuously along the length of the tube from a zone spaced from the end thereof out to the end of the tube.

Also, it is an object of the present invention to provide a new tube expander tool for fastening tubes into tube holes of tube sheets or the like by means of which a better expanded joint between the tube end and a tube sheet may be obtained in less time Without dependence on the skill of the operator.

Moreover, it is an object of the present invention to provide a new tube expander tool of rugged construction which can be operated with facility to perform a desired tube expanding operation.

Finally, it is an object of the present invention to provide a new tube expander tool construction which satisfies the existing need in the art, solves the problems indicated, eliminates difiiculties present with the use of prior tube expanders, generally improves tube expanding procedures, and obtains the foregoing advantages and desiderata in an effective and simple manner.

These and other objects and advantages, apparent to those skilled in the art from the following description and claims, may be obtained, the stated results achieved, and the described difiiculties overcome by the methods, steps, .operations, procedures, structures, combinations, arrangements, subcombinations, parts and elements which comprise the invention, the nature of which is set forth in the following general statement, preferred embodiments of which-illustrative of the best modes in which applicant has contemplated applying the principlesare set forth in the following description and shown in the drawings, and which are particlarly and distinctly pointed out and set forth in the appended claims forming part hereof.

The nature of the discoveries and improvements of the present invention may be stated in general terms as preferably including in tube expander tool construction, an electric drive motor, means for driving the motor selectively with a drive cutoff upon developing a predetermined drive torque, or with direct line current drive with out automatic cutotf; a driven expander cage, roller tube expanding members carried and driven by the expander cage; a taper pin or mandrel movable axially of the expander cage within the roller members; means for driving the mandrel from the motor when the motor is operated in one direction with torque drive cutoff to move the mandrel axially of the expander cage to change the expanding diameter setting of the roller members, and means for driving the expander cage and rollers with a fixed roller diameter setting when the motor is operated in reverse direction.

By way of example, several embodiments of the improved tube expander tool structure of the present invention are shown in the accompanying drawings forming part hereof, wherein:

Figure 1 is a diagrammatic side elevation of a tube expander tool embodying the invention;

Fig. 2 is an enlarged longitudinal sectional view of the'tool shown in Fig. l inone position of operation;

Fig. 3 is a view similar to Fig. 2 showing the tool in another position of operation;

Fig. 4 is a sectional view taken on the line 4-4, Fig. 3;

Fig. 5 is a sectional view taken on the line 5--5, Fig. 3;

Fig. 6 is an enlarged section taken on the line 6-6, Fig. 3;

Fig. '7 is a view similar to Fig. 2 of a modified form of tool in one position of operation;

Fig. 8 is a view similar to Fig. 3 of the construction shown in Fig. 7 in another position of operation;

Fig. 9 is a reduced sectional view taken on the line 9-9, Fig. 8;

Fig. 10 is a view similar to Figs. 2 and 7 showing another modified form of tool in one position of operation;

Fig. 11 is a view similar to Fig. 10 showing the tool in another position of operation;

Fig. 12 is a section taken on the line 12l.2, Fig. 10;

Fig. 13 is a section taken on the line 1313, Fig. 10;

Fig. 14 is an enlarged view of a portion of Figs. 2, 7 and 10 showing parts of the tool at the start of the tube expanding operation;

Fig. 15 is a view similar to Fig. 14 showing the parts in the position assumed during the next stage in the tube expanding operation;

Fig. 16 is a view similar to Figs. 14- and 15 showing the parts at the conclusion of the tube expanding opera-- tion; and

Fig. 17 is an enlarged view of a portion ofFig. 16.

Similar numerals refer to similar parts throughout the various figures of the drawings.

Referring to Figs. 1 through 6, and 14 through 17, a tool embodying the improvements of the present invention is generally indicated at 1 and includes a driver shank 2 having a hole 3 therethrough adapted to receive a pin 4 (Fig. l) for connecting tool 1 to the chuck 5 of a typical tube expander motor drive head generally indicated at 6. The motor drive head 6 is of standard construction and includes an electric motor, not shown Within the hand grip housing 7 supplied with power through line 3 and controlled by trigger switch 9.

The motor drive head 6 is equipped with usual motor circuit control devices which cause the motor to rotate in one direction, say clockwise looking from the left to the right of Fig. 1, when trigger 9 is actuated and when motor drive head 6 is pushed axially forward against an abutment, thus rotatably driving chuck 5 in a clockwise direction as shown by the arrow 1% in Fig. l. The control devices for the motor automatically cut off the motor drive when a predetermined amount of torque is veloped during chuck rotation in a clockwise direction. In the control devices for automatic torque cutoff of the motor drive, the control device is actuated by amperage to the motor when the amperage reaches a value proportional to the torque resistance of the tube being expanded.

The motor of motor drive head 6 can also be rotated under full line current in a counterclockwise direction when trigger switch 9 is actuated and when motor drive head 6 is held but not pushed axially to the right (viewing Fig. 1) against an abutment. The motor drive head 6 thus far described, per se, is a prior known device and forms no part of the present invention except as combined with and operated as a drive device for the improved tube expander tool of the present invention.

In accordance with the present invention, the driver shank 2 of tool 1 has a head portion 11 on which a driver cage 12 is mounted by threads 13, cage 12 being secured to head 11 by set screws 14 (Fig. 4) extending through a driver cage sleeve 15. The driver cage 12 is generally tubular in shape with a tubular wall 16 exteriorly threaded at 16a. The tubular wall 16 is diametrically slotted substantially throughout its length by forming longitudinal slots 17 therein. The forward end of driver cage 12 is provided with a reduced neck portion 13 having an axially extending tubular expander cage 19 mounted therein by set screws 20. Thus, expander cage 19 rotates with and in the direction of rotation of motor drive head 6.

A retainer housing formed of similar separable members21 is mounted within andmovable axially of tubue lar wall 16 of driver cage 12, saidmembers 21 having diametrically opposed lugs 22 extending outwardly through slots 17 beyond the threaded periphery of the tubular wall 16. A feed nut 23 is threaded onto threads 16a of tubular wall 16 and a cooperating retainer nutv 24 assembled with feed nut 23 also is threaded onto threaded periphery 16a of tubular wall16. The nuts 23 and 24 engage lugs 22 to hold the members 2-1 assembled together as shown, bearing washers 25 preferably being interposed between lugs 22 and nuts 23 and 24. Threaded movement of nuts 23 and 24 along threads 16a. of tubular wall 16 may be tensioned by adjustment of cap screw 26.

A pair of combined radial and thrust bearings 27 are mounted within the retainer housing formed by members 21 andthe bearings 27 have journalled therein the enlarged end 28 of mandrel 29 by shoulder flange 28a. Mandrel 29 extends longitudinally of tool 1 through expander cage 19, being formedat its forward end witha taper pin portion 30.

The forward end of expander cage 19 is provided with a series of slots 31 which are slightly slanted with respect to and extend generally longitudinally of the axis of expander cage 19. Expander rolls 32 are mounted in slots 31, rolls 32. being tapered to conform to the taper of taper pin portion of mandrel 29. Thus, the outer surfaces of expander rolls 32 lie in a circumscribing cylindrical surface the diameter of which can be changed depending.

on the relative location of taper pin portion 30 with respect to rolls 32.

An adjustable stop collar 33 is slidably mounted on expander cage 19, and collar 33 may be held in any desired adjusted position by set screw 34.

In operation of the improved tube expanderl, expander cage 19 is inserted into the end 35 of the tube 36 to be expanded within a tube hole 37 formed in tube sheet 38 to a predetermined depth which is gauged by stop collar 33, so that the parts of the tool 1 generally are in the position shown in Figs. 2 and 14'. The adjustment of stop collar 33 previously has been determined with reference to the thickness of the tube sheet 38 so that the outer ends of roll 32 are approximately in line with the right hand or inner surface 39 of tube sheet 38 as shown in Figs. 2 and 14.

Drive head 6 is then actuated to start the motor thereof in a clockwise directionfacing tube sheet 38-by pushing the motor axially toward tube sheet 38 which acts as an' abutment for the tool 1 and drive head 6 through the medium of stop collar 33, trigger switch 9 being actuated at the same time that motor head 6 ispush'ed axially toward tube sheet 38. Rotation of the motor, through chuck 5 and driver cage 12, rotates the expander cage 19 ina clockwise direction.

Meanwhile the operator with his other hand-grasps the feed and retainer nut assembly 23-24, which may be exteriorly knurled as indicated at 40 in Fig. l and holds the same against rotation. This causesnut assembly 23-24 to move to the right along driver cage threads 16a thereby moving retainer housing members 21 axially of the tool to the right or toward tube sheet 38. Move ment of the retainer cage members 21 in this manner causes mandrel 29 to move forward through expander cage 19 so that the taper pin portion 30 thereof forces the rotating rolls 32 outward to increase the diameter of the circle circumscribed by rolls 32. The rolls 32 meanwhile roller expand an annular band as indicated at 41 in Figs. 3 and 15 within tube end 35.

Prior to operation of the motor, the motor control devices are set to shut off the motor when a predetermined torque has been developed, and this torque in turn is calculated as a function of the desired inside expanded tube diameter 41. Thus, when the desired expanded tube diameter 41 has been formed by rolling and cold working of themetal in the tube wall 35, resistance tofurthe'r work- 3 ing is=such= that the calculatedl or predetermined torqueis being. delivered by motor drive device 6 thereby cutting off further operation of the motor which in turn causes expander cage 19 of: tool 1 to cease to rotate in a clock- Figs. 3 and 15 illustrate the position of wise direction. the parts at this time, the mandrel 29 having been projectedtothe right to a position such that the rolls 32 have performed a predetermined amount of rolling and tube expanding as indicated at 41.

At this time, the operator releases his hold on knurled nut assemlby 2324 so that the nut assembly will not move relative to driver cage member 12, and the outside diameter of the circle circumscribed by rolls 32 remains at the predetermined setting developed. The motor drive device 6 is now actuated by actuating trigger switch 9 without pressing motor device 6 toward the tube sheet which causes rotation of the motor in a counterclockwise direction with full power and without cutoff. Rotation of the motor in this direction thus rotates the expander tool assembly including expander cage 19 in a counterclockwise direction and due to the described slight angularity of rollers 32 with respect to the axis of tool I, the rolls 32 self-feed the tool outward of the tube 36 from the position of Figs. 3 and 15.

During this outward self-feeding movement of the tool, rolls 32 cold roll and expand the inner surface of the tube end 35' progressively outward to the end of the tube 36, from the position of the parts shown in Figs. 3 and 15 to the position shown in Fig. 16 whereby the entire end portion 35 of the tube within hole 37 in tube sheet 38 is expanded to an increased inner diameter as indicated.

slight flange 4-3 at the extreme end of tube 36 beyond the lefthand surface 44 of tube sheet 38. Furthermore, sometimes one or more annular grooves 45 (Fig. 17) are formed intermediate the ends of hole 37 in tube sheet and when such grooves are provided, the expanding and cold working of the tube 36 within tube sheet hole 37 forms the metal in the wall of the tube end 35 slightly outwardly into grooves 45 as indicated at 46 in Fig. l7 thereby assisting in fixing tube end 35 within hole 37 in tube sheet 38.

As the tool 1 is being used to expand tube end 35 from the position of the parts shown in Fig. 15 to the position of the parts shown in Fig. 16, if it becomes necessary for any reason to stop expanding operation of the tool or to withdraw the tool, such stoppage or withdrawal may be accomplished by holding nut assembly 23-24 while expander cage 19 is rotating counterclockwise, which results in movement of nut assembly 23-24 from the position of Pig. 3 toward the position of Fig. 2, thereby retracting taper pin portion 30 and reducing the diameter of the circle circumscribed by the outer surfaces of rolls 32. The end of expander cage 19 can then be withdrawn from within the tube end without any damage to the tube or the expander.

Because all of the drive torque is transmitted to rolls 32 by expander cage 19, and not through mandrel 29, exceedingly small tubes can be expanded with the improved tool without danger of tool breakage. in the use of prior tube expanders, where small tubes are to be expanded without danger of tool breakage, the same can only be accomplished by using a series of very light passes which may result in excessive cold Working of the metal in the tube ends, undesirable in many instances. In the use of the tube expander of the present invention, small tubes can be rolled to expand the same to the proper degree in a single pass without tool breakage.

On the other hand, with larger tube diameters the tube expander of the present invention may be used to expand a tube end with a series of passes, and the amount of expansion per pass can be regulated to any desired value without change of the mandrel to obtain different or successive amounts of expansion.

The tube sheet 38 to which the tubes 36 are joined usually are steel, naval brass, copper-nickel, or sometimes stainless steel plates, or forgings; and the tubes may be formed of any one of a number of metals, such as alumi num, brass, copper, steel or stainless steel. In expand ing the ends of tubes made of certain of such metals, careful control must be exercised and the expander tool of the present invention enables such control to be maintained because the extent of tube rolling can be predetermined.

Referring to Figs. 7, 8 and 9, wherein a modified form of expander tool generally indicated at 47 is shown, the tool 47 has a driver shank d8 similar to the driver shank 2 and is provided with the same mandrel 29 and expander cage 19 as in tool 1. Tool 47, however, has a head portion 49 terminating in a tubular extension 50 internally threaded at El. and closed by an end Cover 52 in Which expander cage 15 is mounted by set screws 53.

A retainer member '4 is threaded in threads 51 for movement axially of head portion 49, and bearings 55 are mounted in retainer 54 in which the enlarged end 28 of mandrel W is journalled by shoulder flange 28a. An elongated pinion member 56 extends rearwardly from retainer member 54 and meshes with planet pinions 57 mounted on head portion 49. A control sleeve assembly generally indicated at 53 is axially slidably journalled on head portion 49 movable between the positions shown in Figs. 7 and 8. A control handle 59 projects from the control sleeve assembly 53 and within sleeve 58 a ring gear 6% is mounted adapted to mesh with planet gears '57 when control sleeve 58 is in the position shown in Pig. 8. The expander cage of tool 47 is provided with a stop collar 33 and expander rolls 32 and is otherwise constructed in the same manner as tool ll.

In operation of the tool 47, expander cage 19 is inserted into end of tube 36 until stop collar 33 abuts tube sheet 33 in the same manner that tool 1 is used, when the parts are in the position shown in Fig. 7. With the motor drive head for the tool operating, tool handle 59 is pushed to the right to the position of Fig. 8 thereby engaging planet gears 57 with ring gear 6% and producing a differential rate of rotation between head portion 49 and retainer 54 thus projecting mandrel 29 forwardly through expander cage 19 from the position shown in Fig. 7 to the position shown in Fig. 8 when torque cutoff operates when a predetermined torque has been developed corresponding to the desired expanded tube diameter ll to be obtained.

Pressure on handle 59 is then released and the sleeve assembly is moved to disengage ring gear 69 from planet gears 57 the motor drive direction is reversed, producing the same outward feeding of the expander tool from the position of Figs. 8 and 15 to the position of Fig. 16 as explained above in connection with operation of tool ll.

Referring to Figs. l0, l1, l2 and 13, wherein another modified form of expander tool generally indicated at 61 is shown, the tool 61 has a driver shank 62 similar to the driver shank 2 and is provided with a mandrel 63 having a taper pin portion Elli similar to the mandrel in the tool 1, and also with expander cage 1% as in tool 1.

Tool ell, however, has a head portion 64 on which a tubular sleeve 65 is mounted closed at its other end by an end cover 66 in which expander cage 19 is mounted by set screws 67. Sleeve 65 is provided with longitudinal, diametrically located slots 68 through which lugs 69, threaded at 7th, project; the lugs 6% extending from a retainer member Tl slidably mounted within tubular sleeve 65. Enlarged head 72 of mandrel 63 isjournalled within retainer 71 for movement therewith and an outer sleeve 73 is journalled on sleeve 65, spaced therefrom. Sleeve 73 is internally threaded at 74 to mesh with threads on lugs 69.

A control sleeve assembly generally indicated at 75 is axially slidably journalled on sleeve 65, movable between the positions shown in Figs. 10 and 11. A control handle 76 projects from the control sleeve assembly 75 and teeth 77 are provided on sleeve 75 adapted to mesh with test 1 78 on outer sleeve 73 when control sleeve 75 is held in the position shown in Fig. 11. The expander cage 19 of tool 61 is provided with a stop collar 33 and expander rolls 32 and is otherwise constructed in the same manner as tool 1.

in operation of the tool 61, expander cage 19 is inserted into end 35 of tube 36 until stop collar 33 abuts tube sheet 38 in the same manner that tool 1 is used, when the parts are in the position shown in Fig. 10. With the motor drive head for the tool operating, tool handle 76 is pushed to the right to the position of Fig. 11 thereby engaging sleeve 75 with sleeve 73 through teeth 77 and 73 and holding sleeve 73 against rotation. Retainer 71 rotating with sleeve 65, by engagement of threads 70 and 74, moves from the position of Fig. 10 to the position of Fig. ll. when torque cutoff operates when a predetermined torque has been developed corresponding to the desired expander tube diameter 41 to be obtained. Pressure on handle 76 is then released and the sleeve assembly 75 is moved to disengage teeth 77 and '78. The motor drive is then reversed, producing the same outward feeding of the expander tool from the position of Figs. 11 and 15 to the position of Fig. 16, as explained above in connection with the operation of tool 1.

In each of the three modifications of the improved tube expander tool of the present invention, the same operative result is obtained, namely, a constant rate of expansion is produced at a fixed location within the tube end until a predetermined inside diameter is reached and then the expanding tool moves outwardly of the tube to the end thereof to uniformly expand the tube end progressively to a predetermined, fixed and uniform inside diameter.

in each modification this operative result is obtained by holding one part of the tool against rotation while the tool is rotated in one direction to feed the tapered pin end of the mandrel forwardly through the expander cage to obtain the desired roll setting. The previously held tool part is then released and the tool is rotated in the opposite direction to feed the expander tool outward of the tube end with the predetermined fixed setting of the expanding rolls maintained during the expanding operation.

Accordingly, the present invention provides an improved tube expander tool construction with which small tubes can be expanded with a minimum danger of tool breakage, with which the inside diameter of the expanded tube can be controlled to any desired value, with which the tool can be withdrawn from the tube at any time without damage to the tube or expander, with which the expander may be used to perform a series of expanding passes when desired without changing the mandrel, and with which a better expanded joint may be obtained in less time without dependence on the skill of the operator. Moreover, the improved tube expander tool of the present inventon enables the described new tube expanding operation to be carried out with a maximum of precision and accuracy, thereby accomplishing the new results, overcoming the prior art diificulties and solving the longstanding problems in the art hereinabove described.

In the foregoing description certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are utilized for descriptive purposes herein and not for the purpose of limitation and are intended to be broadly construed.

Moreover, the description of the improvements is by way of example and the scope of the present invention is not limited to the exact details illustrated or to the specific embodiments shown.

Having now described the features, discoveries and principles of the present invention, the construction, operation and use of several embodiments of the improved tube expander tool, and the advantageous, new and useful results obtained thereby; the new and useful methods, steps, operations, procedures, structures, combinations, arrangements, subcombinations, parts and elements which comprise the invention, and mechanical equivalents obvious to those skilled in the art are set forth in the appended claims.

I claim:

1. In tube expander construction, a tubular driver cage, an expander cage connected to the driver cage for rotation therewith and having a tubular wall adapted to be inserted and rotated in a tube to be expanded, the expander cage tubular wall having slots formed therein, a plurality of similar tapered expander rolls supported in said slots and revolved by said expander cage about the cage axis and movable radially of the cage axis, a mandrel journaled extending axially within and movable axially of the driver and expander cages and having a taper pin portion internally engagaing and radially supporting said rolls, means for rotating the driver and expander cages'and rolls in one direction, means operably connected with the mandrel and selectively actuated by the rotating driver cage when the driver cage is rotated in said one direction to move the mandrel axially relative to the driver and expander cages and rolls to thereby move the rolls by the taper pin portion radially outward of the expander cage to a given desired position, and means for rotating the driver and expander cages and rolls in the opposite direction with the rolls maintained in said given position.

2. Tube expander construction as defined in claim 1 in which the means selectively actuated by the rotating driver cage includes an internally threaded feed nut threadably engaged with and surrounding a portion of the driver housing; in which the driver housing has tubular Walls; in which retainer means is axially slidably mounted within the driver housing tubular walls; in which the mandrel is journaled in the retainer means through thrust bearing means mounted in the retainer means so that the mandrel is rotatable with respect to said retainer means but axially movable therewith; and in which the drivcr nut is engaged with said retainer means through slot means formed in the driver cage tubular walls for axially moving the retainer means with respect to the driver cage when the driver nut is retained against rotation while the driver cage is rotated in said one direction.

3. Tube expander construction as defined in claim 1 in which the driver housing has tubular walls; in which the means selectively actuated by the rotating driver cage includes an externally threaded retainer member positioned surrounded by and threadably engaged with the driver cage tubular walls; in which the mandrel is journaled in the retainer member through thrust bearing means mounted in the retainer member so that the re tainer member is rotatable with respect to said mandrel but the mandrel moves axially upon axial movement of the retainer member; in which the retainer member includes an axially extending pinion portion; in which at least one pinion gear is journaled on the driver housing and operably engaged with the retainer member pinion portion; in which a control sleeve is mounted journaled on and surrounding the driver cage for limited axial movement with reference to said driver cage; in which the control sleeve includes a ring gear mounted on said sleeve and operably engageable with the driver cage pinion gear upon the control sleeve being moved axially to a selected position with reference to the driver cage, so that by placing the control sleeve in said selected position and retaining the control sleeve against rotation, the retainer member is held against rotation and moves axially with respect to the driver cage when the driver cage is rotated in said one direction.

4. Tube expander construction as defined in claim 1 in which the means selectively actuated by the rotating driver cage includes an internally threaded feed nut mounted journaled on and surrounding a portion of the driver housing in a fixed axial position; in which the driver housing has tubular walls; in which retainer means is axially slidably mounted within the driver housing tubular walls; in which the mandrel is journaled in the retainer means through thrust bearing means mounted in the retainer means so that the mandrel is rotatable with respect to said retainer means but axially movable there with; in which the retainer means includes externally threaded portions extending through slot means formed in the driver cage tubular walls; and in which said externally threaded portions are threadably engaged with the feed nut internal threads, so that by retaining the feed nut against rotation the retainer means is moved axially with respect to the driver cage when the driver cage is rotated in said one direction.

References Cited in the file of this patent UNITED STATES PATENTS 672,448 Mackenzie Apr. 23, 1901 682,726 Lovekin Sept. 17, 1901 746,579 Roedmann Dec. 8, 1903 1,601,329 Slesazeek Sept. 28, 1926 1,752,408 Zein Apr. 1, 1930 2,355,852 Fisher Aug. 15, 1944 2,389,098 Welch Nov. 13, 1945 2,409,219 Maxwell Oct. 15, 1946 2,546,756 Knowlton Mar. 27, 1951 2,575,938 Brenneke Nov. 20, 1951 2,736,950 Mathews Mar. 6, 1956 

